Endoscopic procedures for treating abnormal pathologies within the alimentary canal system and biliary tree (including the biliary, hepatic, and pancreatic ducts) are increasing in number. The endoscope provides access to the general area of a desired duct using direct visualization. However, the duct itself must be navigated using a catheter in conjunction with fluoroscopy and guidewires. Catheters are known for treatment of targeted anatomical regions. Known methods and devices for using biliary catheters for accessing the biliary tree for performing catheter procedures are disclosed in Weaver et al., U.S. Pat. No. 5,397,302, Karpiel, U.S. Pat. No. 5,320,602, and Windheuser et al., U.S. Pat. No. 6,096,099, each of which is herein incorporated by reference. In general, for treatment of an abnormal pathology within a patient's biliary tree, an endoscope is first introduced into the mouth of the patient. The endoscope includes a proximal end and a distal end, and has a lumen extending longitudinally between the proximal and distal ends. The endoscope is guided through the patient's alimentary tract or canal until an opening at the distal end of the endoscope is proximate the area to receive treatment. At this point, the endoscope allows other components, such as a catheter, to access the targeted area.
For visualization or treatment within the biliary tree, the distal end of the endoscope is positioned proximate to the papilla of vater leading to the common bile duct and the pancreatic duct. A catheter is guided through the lumen of the endoscope until a distal tip of the catheter emerges from the opening at the distal end of the endoscope. The distal end of the catheter is then guided to the orifice to the papilla of vater (located between the sphincter of oddi) leading to the common bile duct and the pancreatic duct. A guidewire may be used in conjunction with the catheter to facilitate accessing a desired location within the biliary tree. This is known as guidewire cannulation. The guidewire is inserted in an opening at a proximal end of the catheter and guided through the catheter until it emerges from the distal end of the catheter. In order to properly position the guidewire and the catheter during this process, an operator may separate the guidewire from the catheter and control the guidewire separately. In addition, the operator will often extend the guidewire a few millimeters, e.g., 1 mm to 5 mm, outside of the catheter and advance the two together. This provides even more of a tapered system to advance into small openings, sphincters (that are contracting or opening) and through strictures. However, if the guidewire meets resistance, it may be pushed back into the catheter, requiring the operator to attempt to manually pinch both the guidewire and the catheter together. Unfortunately, manually pinching the guidewire and catheter together has proven unreliable and cumbersome for the operator. Accordingly, a locking device is desired whereby the operator can selectively secure the guidewire to the catheter during guidewire cannulation in order to help advance the guidewire and catheter together when resistance is met or advance the guidewire and catheter separately, if desired. Further, a locking device is desired that frees the operator's hands for other tasks.